Numerous medical disease conditions that result from prolapse of internal organs and/or anatomical structures may be treated by providing support to the area of prolapse with a surgical implant such as a sling, a patch, or a mesh. Such implants are useful to treat, for example, stress urinary incontinence in female patients.
Various physiological conditions cause urinary incontinence in women. Stress urinary incontinence generally is caused by two conditions that occur independently or in combination, Intrinsic Sphincter Deficiency (ISD) and Bladderneck Hypermobility. ISD is a condition where the urethral sphincter valves fail to coapt properly. When functioning properly, the urethral sphincter muscles relax to enable the patient to void, and the sphincter muscles are otherwise constricted to retain urine. ISD may cause urine to leak out of the urethra during straining activities. Hypermobility is a condition where the pelvic floor is weakened or damaged causing the bladder neck and proximal urethra to descend in response to increases in intra-abdominal pressure. When intra-abdominal pressure increases (due, for example, to strain resulting from coughing), the hypermobility condition may cause urine leakage. Some women suffer from a combination of ISD and hypermobility.
The methods for treating stress urinary incontinence include placing an implant to provide support, elevation, or a “back stop” to the bladder neck and proximal urethra. Providing support to the bladder neck and proximal urethra maintains the urethra in the normal anatomical position, elevation places the urethra above the normal anatomical position, and the “back stop” prevents descent according to the so-called hammock theory.
One problem encountered following surgical intervention using an implant such as a sling or a patch to treat urinary incontinence is urinary retention resulting from excessive tension applied to the urethra. Overtensioning may also cause pressure necrosis and/or urethral erosion. One approach to alleviate these problems entails stretching the implant by inserting a catheter into the urethra and applying downward force. This procedure is imprecise and is contraindicated for patients with ISD as it may further damage the urethral sphincter. Another more invasive approach entails surgically removing the implant. Removal of such a surgical implant, which may require dissection, may cause irreparable damage to an already weakened or damaged pelvic floor. Accordingly, there is a need in the surgical arts for a surgical implant that may be expanded while positioned in the body. There is a further need for a precise and minimally invasive surgical method for expanding a surgical implant after it has been placed in the body.